Well perforating assembly and perforating unit therefor



1962 B. M. CALDWELL ET AL 3,067,679

WELL PERFORATING ASSEMBLY AND PERFORATING UNIT THEREFOR Filed Oct. 8, 1954 5 Sheets-Sheet l INVENTORS.

Dec. 11, 1962 B. M. CALDWELL ETAL 3,

WELL PERFORATING ASSEMBLY AND PERFORATING UNIT THEREFOR Filed Oct. 8, 1954 5 Sheets-Sheet 2 G 4 L 0 5 MW L a z 2 8 G 5 6 0% 2 208 G 20 fi 5 5 0:. m x 7 /7 4 6 .4 5 llli 11 v 5 o o a M z a G v 8 O 2 G 0 M M M a l 5 5 wa 5 M I J-Mezozo a 0W5,

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Dec 11, 1962 B. M. CALDWELL ETAL WELL PERFORATING ASSEMBLY AND PERFORATING UNIT THEREFOR Filed Oct. 8, 1954 5 Sheets-Sheet 3 51/7/65 A7. CHAD/V544, HHEBOLD 0. OWL-Al,

IN V EN TORS.

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1962 B. M. CALDWELL ETAL 3,067,679

WELL PERFORATING ASSEMBLY AND PERFORATING UNIT THEREFOR Filed Oct. 8, 1954 5 Sheets-Sheet 4 FIG. 10.

1962 B. M. CALDWELL ETAL 3,067,

WELL PERFORATING ASSEMBLY AND PERFORATING UNIT THEREFOR Filed Oct. 8, 1954 5 Sheets-Sheet 5 47'7'0ENE V5.

3,067,679 Patented Dec. 11, 1962 ice 3,067,679 WELL PERFORATING ASSEMBLY AND PERFORATING UNIT THEREFOR Blake M. Caldwell and Harrold D. Owen, Fort Worth,

Tern, assignors to Halliburton Company, a corporation of Delaware Filed Get. 8, 1954, Ser. No. 461,236 13 Claims. (Cl. 102-20) This invention relates to well perforating assemblies, and particularly assemblies adapted to be run through well tubing to be fired after emergence from the lower end of such tubing. This invention also relates to perforating units for use in such assemblies.

In the completion of wells drilled by the rotary method, it has long been the practice to perforate casing set in the well adjacent the producing formation for the purpose of providing ingress to the well from said formation. Such perforating formerly was done before the well was capped and while the heavy drilling mud was within the casing, and after perforating, the well was completed for production by removing the mud, running tubing into the well and capping same. More recently, however, the practice of running in the tubing, affixing the well head equipment, and replacing the drilling mud with clean fluid, all prior to perforating, has gained considerable popularity in the field, and in this method the perforating assemblies used must be adapted to be lowered through the tubing until, 'upon emergence therefrom in the vicinity of the oil-bearing formation, the perforating can be accomplished.

The practice of the more recent method has been handicapped, however, for a considerable period of time because of lack of proper perforating equipment. Since the effectiveness of the perforating job is, in general, a function of the length and size of the particular perforating units used, whether bullet guns or shaped charges, under the former system adequate perforating was obtained through use of horizontally fixed bullet barrels or shaped charges having a length approaching as far as feasible the diameter of the casing, but inasmuch as the diameter of the production tubing is, of course, considerably less than that of the casing, the use of such apparatus is impossible in the newer well completion method.

Perforating means, such as gun bodies, containing angularly positioned shaped charges and having a diameter somewhat less than the production tubing, have been suggested, and by this means a compromise is effected whereby part of the desired increased length of charge is attained while at the same time limitations imposed by the diameter of the tubing are adhered to. Obviously, however, units such as this cannot in firing power he expected to equal or exceed the above horizontally disposed units.

In order to remain within the aforesaid tubing diameter limits imposed by the fact that the perforating assembly must be lowered through the tubing and at the same time obtain the advantage of horizontally disposed perforating units, it has been suggested that the assembly be so arranged that during the lowering of same through the tubing the perforating units are in vertical alignment with the axis of the tubing, but upon emergence of the assembly from the lower end of the tubing, said units be permitted to pivot to a horizontal firing position. Such apparatus is disclosed in Patent No. 2,543,814 to W. H. Thompson et al. dated March 6, 1951, and entitled Means and Method of Tilting Explosive Charges in Wells. An improvement upon the Thompson et al. patent, which patent does not provide for a retraction of the apparatus after emergence from the bottom of the tubing, resides in an application for United States Letters Patent filed February 19, 1954, by Blake M. Caldwell and Joe P. Wier, Serial Number 411,349, entitled Tilting Charge Well Perforating Assembly.

None of the aforesaid apparatus provides, however, means whereby the perforating units can be lowered in vertical disposition with respect to the tubing until the assembly emerges from the end of the tubing, whereupon tilting of the units to the horizontal position can be controlled from the surface, the disposition of the units being independent of the tubing. Nor does it provide effective means whereby inadvertent firings of the units can be protected against, in the event that said units are not properly horizontally disposed. And it does not provide means whereby, in the event of failure to fire or other difiiculty, the entire assembly can be withdrawn through the tubing to emerge therefrom at the surface of the well unarmed and locked in vertical position.

The instant invention contemplates a perforating assembly having the foregoing attributes and, therefore, affording to users of the apparatus a very considerable degree of safety while at the same time providing a tool of utmost economic value to field operations involving the perforating of a well after the setting of the tubing, the removal of the mud, and the caping of the well. Such economic value arises by virtue of the fact that the instant invention provides in a perforating assembly adapted for lowering through the tubing an arrangement whereby full advantage may be taken of the desirability of firing the perforating units from a horizontal position while at the same time preserving complete control of the assembly from the surface of the well.

It is, therefore, the principal object of this invention to provide an improved perforating assembly adapted for lowering through the production tubing of a well and firing after emergence from said tubing.

It is another object of this invention to provide such an assembly wherein the perforating units, during progress through the tubing, are disposed vertically but are adapted to assume a horizontal firing disposition at the will of the operator at the surface.

It is yet another object of this invention to provide such an assembly equipped with a safety firing mechanism rendering it impossible to inadvertently fire the perforating units unless such units are in the correct firing position. In this regard, it is still another object of this invention to provide in such an assembly means whereby the aforesaid correct firing position may be predetermined.

It is yet another object of this invention to provide means in such an assembly whereby the assembly, upon failure of the perforating units to fire or in the event the operator does not desire to fire same after their emergence from the bottom end of the tubing, may be withdrawn through the tubing and the perforating units locked in retraction from firing position. In this invention, the foregoing may be accomplished even after the perforating units have assumed firing position.

It is another object of this invention to provide means in such an assembly whereby the assembly may be withdrawn as aforesaid through the tubing to emerge from the upper end of said tubing still locked in non-firing position and disarmed against inadvertent detonation.

It is still another object of this invention to provide a perforating unit for use in such an assembly.

These and other objects and features and advantages of the present invention will be apparent from a consideration of the following specification taken in conjunctio with the accompanying drawings in which:

FIGURE 1 shows a front elevational view of a per- Irating assembly incorporating the instant invention.

FIGURE 2 shows a side elevational view thereof. FIGURE 3- shows a longitudinal sectional view of said :rforating assembly taken on the line 33 of FIGURE the perforating units therein being in vertical dispotion.

FIGURE 4 shows the identical view shown in FIG- RE 3 with said perforating units pivoted to horizontal ing position.

FIGURE 5 shows a cross-sectional view of the aforeid perforating assembly taken on the line 55 of FIG- RE 3.

FIGURE 6 shows a cross-sectional view of said perratin-g assembly taken on the line 66 of FIGURE 4. FIGURE 7 shows an enlarged sectional view of the ing mechanism for the perforating assembly. FIGURE 8 shows the same view of said firing mechann, the parts therein being in different disposition. FIGURE 9 shows a partial view of the perforating sembly wherein is incorporated means for connecting l8 such perforating assembly to another in tandem. FIGURE 10 shows a side view, partially broken away,

the firing switch for the perforating assembly.- FIGURE 11 shows a front view of said switch. FIGURE 12 shows a schematic wiring diagram of efiringcircuit. FIGURE 13 shows a side elevational view of a perrating assembly constituting a modification of the intnt invention. In this view a portion of the assembly s been broken away. FIGURE 14 shows the same view as said modification ierein the perforating units are pivoted to firing posi- In as distinguished from vertical position. FIGURE 15 shows a partial front elevational view of e modification. In its general aspect the invention comprises a firing ad 10 to which is connected a conductor 12, which nductor passes through the cable from the surface. 1e cable is not shown but supports the assembly in :ll-known manner. Carried by the'firing head 10 is elongated carrier 14 through which passes the detotor fuse 16 detonated by the firing head. Said detoting fuse 16 is retained in place with respect to the aped charges 18 by grooves in the charge caps and e charges are pivotally mounted within the carrier d are resiliently urged to horizontal position. Said arges are, however, by interlock means, such as the tents 20, held interlocked in axial disposition with reect to the carrier. A release means, which could be lenoid operated or other electrically operated stop means it which is shown here as the explosive cartridge or uib 22, is electrically connected through the conductor l to the switch 26 and abuts the detent a of the lttom shaped charge. Upon firing of the squib, the

tttom shaped charge is permitted to resiliently pivot horizontal position. Pivoting of the bottom shaped large releases the next shaped charge for similar reient pivotal movement to horizontal position, and the mess is repeated to permit each charge to assume 'ingdisposition.

Additionally, control means are provided whereby the ,aped charges may not be fired from the surface in e event they are prevented, as by well obstructions, o'm attaining a predetermined proper firing position. bus, arelease arm 28 is pivoted to the carrier above euppermost shaped charge, which release arm is proded with a detent 20b and through plunger 30 is con- :cted to the switch 26. The release arm, which comises an arming means, must, after firing of the squib 2, travel through a predetermined angle to close the ain firing circuit and thus arm the assembly. Thereare, if a well obstruction prevents the aforesaid travel 5 the release arm, the shapedcharges may not be fired. The apparatus is adapted to be lowered. through the tubing 32 to a position below the lower end thereof, but in the event that after lowering the apparatus through the tubing 32 the operator does not wish to fire the perforating units, or in the event a well obstruction is encountered after firing of the squib 22 which prevents arming of the assembly, the assembly may be withdrawn back through the tubing 32. Such Withdrawal after firing of the squib successively causes the release arm 28 to be cammed against the bottom of the tubing to substantially vertical position, causes the adjacent shaped charge similarly to be cammed to substantially vertical position, and thuscauses interlocking of the detents 20b and 20. Similarly, the next lower shaped charge is cammed to vertical position and is interlocked with the foregoing charge until the entire assembly of shaped charges is substantially vertical inthe tubing 32, the lowermost shaped charge being maintained in vertical disposition by the tubing and maintaining the interlock. Upon egress of the assembly from the top of the tubing, the release arm and each shaped charge 18 are held in vertical position due to the detents 20, and an operator may grasp the lower most shaped charge as it issues from the well. This will serve to retain all the charges in vertical position, ill retain the release arm similarly in vertical position, and will prevent the inadvertent arming and firing of the assembly above the surface of the well.

Hence, the invention embodied in the assembly, as generally described, provides a perforating apparatus capable of being lowered through the well tubing. Perforating units of such perforating apparatus are adapted to be pivoted to horizontal or predetermined angular position for firing, the perforating units each being locked against such pivoting until released under the control of the operator. The assembly may not fire until the per forating units reach predetermined angular position, the assembly maybe withdrawn through the tubing without firing, and the perforating units upon such withdrawal and after egress of the assembly from the upper end of the tubing are locked in the vertical position, and inadvertent arming and firing of the perforating units above the surface of the ground is prevented. 7

Referring now more specifically to the drawings, it will be seen that the assembly is shown, particularly in FIGURES 3 and 4, as lowered through the tubing 32 in the well casing 34, FIGURE 3 showing the assembly during lowering and FIGURE 4 showing the assembly after issuing from the bottom of said tubing and assuming firing position.

The firing head 10 is connected by screws 36 to an adaptor 38, which in turn is connected in common mannerto a cable connector, casing collar locator or the like suspended from the conductor cable, the latter elements not being shown. An O-ring 40 provides a seal between the adaptor and the firing head and a release sub 42 isprovided below the adaptor, said release sub 42 having a depending extension 44. The carrier 14 is in turn supported by the extension 44 and is aflixed thereto by means of screws 46, said screws 46 pivotally carrying bosses 48 which are integral with the release arm 28..

As shown, the carrier 14 is of cylindrical shape and is provided with large apertures 50 to accommodate the pivoting of the release arm 28 and the shaped charges 18. The upper edge of each shaped charge aperture is. adapted team as a stop against over-pivoting by its respective shaped charge. The shaped charges 18 are pivoted on screws 52 by the springs 54, one end 56 of each spring being'connected to the carrier through small holes drilled therein and the other end 58 of each spring being connected to a shaped charge through a hole 60.

in one ofthe groove flanges 62 which are formed integrally with the cap 64 of'each shaped charge 18. To accommodate the release arm 28, a hole 66 is provided for thespring in a boss 68 integral with said release arm.

Each shaped charge 18 consists generally of a conical liner 70, explosive 72, and a booster charge 74, the whole being enclosed in a case 76 and the aforesaid cap 64, a seal being provided therebetween by the O- ring 78, and the cap portions being provided with bosses 80 permitting the charges to pivot on the screws 52. Thus is provided an enclosed and sealed, elongated, generally cylindrical charge housing. It will be observed that the two detents of each shaped charge are formed integrally with and extend from, respectively, the case 76 and a flange 62 of the cap, the two detents on each shaped charge being laterally ofiset the one from the other, but each cooperating pair of detents on alternate charges being in registry.

At the bottom of the carrier 14, secured by screws 82, is a bull nose 84, said bull nose providing a pas sageway 86 and a bore 88 through which passes the conductor 24 which is connected to the explosive squib 22 in the counterbore 90. Said squib 22 projects from the bull nose and acts as a stop against the detent 26a extending from the case 76 of the lowermost shaped charge. The conductor 24 is connected to the switch 26 and current therefrom is adapted to explode the squib upon closing of the squib circuit by the operator, as will be hereinafter more particularly described. Explosion of the squib, of course, permits pivoting by the lowermost shaped charge 18 and successive pivoting by adjacent shaped charges until the release arm 28 in turn is released to pivot angularly outwardly.

Also passing through the passage 86 is the detonating fuse 16. Such a detonating fuse is marketed as Primacord by the Ensign-Bickford Company of Simsbury, Connecticut. It is covered with tubing as a protection against well fluid. The fuse is set off by a blasting cap 92 in the firing head as the result of the current delivered through the switch 26, as will hereinafter be more particularly described. Below the blasting cap 92 is provided an auxiliary booster 94 in contact with the explosive of the detonating fuse, and the fuse passes through a fitting 96, a sealing gland 98, and a back-up sleeve 100, all of which elements afford sealing protection for the fuse. It thereafter passes through the recess 102 formed between one of the bosses 48 and the release arm 28, and hence between the groove flanges 62 of each shaped charge until terminating in the seal 164 in the bull nose 84. Such disposition of the fuse in combination with the groove flanges of the shaped charge caps permits slidable free pivoting of the shaped charges while at the same time retaining the fuse in place. Towards the end of the angular travel of each shaped charge the fuse is pressed between the booster 74 of each shaped charge and the side wall of the carrier to insure positive detonation of the charge.

It will be seen that the groove flange 62 provides a fuse receiving groove that is circularly arcuate about the pivotal axis of the perforating unit 18. The groove lies in an imaginary plane perpendicular to the pivotal axis and extends from a point at the side of the cap 64 to a point on the end of the cap that is adjacent to the longitudinal axis of the perforating unit. The groove thus extends through an arc of about 90 approximately equal to the angle traversed by the perforating unit in swinging from axial disposition to firing position. As seen in FIGS. 4 and 6, the point at the end of the cap to which the groove extends is adjacent the axially disposed booster charge 74.

As clearly seen in FIG. 4, which shows the perforating units 18 in horizontal positions, the upper horizontal face, or detent face, of the detent 26 on the groove flange 62 and the upper horizontal face, or detent face, of the detent a on the case 76 lie in an imaginary plane in cluding the transverse pivotal axis of the perforating unit, extending between the pivot screws 52. Referring again to FIG. 6, it is further seen that the complementary detents 20 on opposite ends of the perforating unit 18 are disposed at equal distances from and on opposite sides of an imaginary plane including the longitudinal axis of the perforating unit and intersecting the pivotal axis of the perforating unit at right angles.

Referring now particularly to the means for firing the explosive squib to permit angular pivoting of the shaped charges 18 and release arm 28 and the means for detonating the detonating fuse, it is seen that a chamber 106 is provided within the firing head 10 and adaptor 38, which chamber houses the switch 26. Said switch is adapted to insure that current is delivered to the explosive squib 22 and to the fuse blasting cap 92 in proper sequence, and is comprised of a common double pole, double throw switch actuated by the plunger 30, which, in turn, comprises a clevis 108 pivotally connected by the screw 110 to the release arm 28 and a rod 112 extending from said clevis through a passageway 114 in the firing head 10. A seal is provided between the rod 112 and the firing head 16 through the O-ring fitting 116, and said rod slides freely therethrough. Referring particularly to FIGURES 7 and 8 and 10 through 12, it will be seen that the rod 112 is provided with holes 140, 1400, 14% and e, hole 140 receiving an upper cotter pin 142 and holes 1400, 14% and 1400 being adapted to receive a lower cotter pin 144. A spring 146 is in compression between the upper cotter pin 142 and the switch arm 148. Such an arrangement enables the switch to be moved up or down in response to travel of the release arm 28. The switch arm 148 extends from a slot, not shown, in the switch housing 150 and is an integral part of the switch actuator 152, said switch actuator being adapted to slide up and down within the housing and carrying the spring-loaded connector members 154. The connector members in the lower position of the switch connect, respectively, contacts 156 and 158 and contacts 160 and 162. In the upper position the connector members connect, respectively, contacts 156 and 164 and contacts 160 and 166.

Contact member 164 is connected to the conductor 12 and a wire 168 connects contact member 164 with contact member 160. Contact member 16-2 is connected to the squib conductor 24 which passes through a bore, not shown, in the firing head and through the seal member 170 to the carrier 14 and, hence, the squib 22. Contact members 156 and 158 are connected to the detonating fuse detonator 92 by wires 172 and 174, respectively, and contact member 158 is connected to ground by a wire 176 soldered to the firing head 10.

Hence, when the plunger 30, including the rod 112, is in the down position and the circuit key at the surface closed, the squib circuit is made up between the conductor 12, the wire 168, one of the connector members 154, and the conductor 24, the squib being thereby fired. In this position of the switch, the detonator circuit is unarmed, the connector member 154 grounding the contact 156. When the plunger 30, however, moves the switch to the up position, the squib circuit is opened and the' detonator circuit closed, connector member 154 connecting contacts 156 and 164, hence forming a circuit between the conductor 12, the aforesaid connector member, the wire 172, the detonator 92, and the wire 174 to ground. Hence, the detonator may fire.

It will be seen, therefore, that the position of the release arm 28 after the firing of the squib 22 determines whether or not the apparatus is armed, and hence, whether or not the shaped charges 18 may be fired. In the event that after the firing of the explosive squib and the successive release of the shaped charges therealbove and the release arm, said release arm does not angularly pivot s-ufliciently far to actuate the switch 26 to its up position, firing of the shaped charges cannot take place. I11 this, of course, the angular travel of the release ar necessary to throw the switch 26 may be predetermin through adjustment of the switch abutting means, such as the cotter pin 144, said cotter pin being inserted in 1e hole 148a as shown, or if a lesser angular travel of re release arm is desired, said cotter pin being insertable 1 one of the other of the holes 14Gb or 148a in the d 112. By this means the apparatus may be set to fire t a release arm disposition of horizontal, or, if desired, t a lesser angle such as, for example, 70 from the vercal. This enables a given assembly to be usable not hly in well casing of relatively large diameter, but also 1 well casing of extremely small diameter. It also rakes possible the assembling of the apparatus so that ffective arming of the assembly takes place upon the each-ing by the release arm end of an outward position ligned with the charge ends.

In operation, the perforating assembly is lowered, as 1own in FIGURE 3, through the tubing 32 to the zone be perforated. During this operation the shaped har-ges 18' and the release arm 28 are in vertical disposion, the explosive squib 22 abutting the detent 28a of re bottommost charge, the upper detent 20 on said harge locking against the corresponding detent 28 of the djacent charge, and so forth, each charge being intericked until the top charge detent 20 abuts the detent 0b of the release arm 28 similarly interlocking with aid release arm.

Upon reaching the desired perforating level, the firing ircuit at the top of the well may be closed, but inas- IUCh as the switch 26 is in down position, the detonator .rcuit cannot close. Rather, the explosive squib 22 is red and destroyed, permitting the lowermost of the prings 54 to pivot the lowermost shaped charge 18 to ring position. Pivoting of the lowermost shaped charge ;leases the next adjacent shaped charge and the shaped arges are successively released until the release arm 8 is itself permitted to pivot. Provided no well obstrucon or otherdifiiculty is encountered which prevents sa-id :lease arm from pivoting through a predetermined numer of degrees, the plunger 30 is raised suificiently to love the switch 26 to the up position, closing the detona- )I firing circuit and permitting current to explode the lasting cap 92, the fuse 16 and the shaped charges 18. will be particularly observed that the assembly below 1e firing head is entirely expendable and may be comused of brittle aluminum which shatters into minute ieces upon firing of the perforating units. These pieces lil tO the well bottom, eliminating possible obstruction 1 the well casing. After firing of the assembly, only le steel firing head 10, the adaptor 38, and the elements )ntaincd therein are returned.-

Upon successful firing of the perforating units, thereire, there is no problam of returning the assembly upard through the tubing. If, however, firing of the per- )rating units is prevented, for example, by a well obruction preventing the release arm 28 from arming the ;sembly, or if a misfire occurs, the assembly may be lfely withdrawn through the tubing. It is only necestry that the cable be raised. In this operation, as the isembly enters the tubing, the release arm 28 is cammed v the bottom of said tubing to vertical disposition and :tained there until the next lower shaped charge is simarly' cammed to vertical position and the detent 20b of re release arm interlocked with the detent 20 of said large. Similarly, as each shaped charge enters the lbing it is cammed to the vertical and interlocked with re shaped charge above. Thus, as the assembly issues om the top of the tubing, the release arm and shaped iar-ges are locked in vertical disposition, and it is only :cessary that an attendant grasp the last and lowermost raped charge as the assembly is entirely removed from l6 tubing to maintain the various perforating units and :lease arm in the aforesaid vertical disposition. Of iurse, since the release arm is not extended, the main raped charge firing circuit is unarmed and'the charges mnot be inadvertently fired.

FIGURE 9 of the drawings shows a means for joining lI'IiGI'S together to effectively extend the length of the well perforating assembly. To accomplish this, a tandem sub 118 is inserted into the bottom of the carrier 14 and afiixed thereto by the screws 128, which tandem sub replaces the bull nose 84. Similarly, the additional carrier 14a is likewise affixed to the tandem sub by screws 122. In this, it will be noted that the design of the carrier 14 is such that any perforating assembly may be cut to desired length and adapted as the carrier 1411.

A tandem release arm 124 similar to the release arm 28 is pivoted as before by screws 126 to the carrier 14, is similarly resiliently angularly urged, and is similarly provided with a detent 28b for interlock with the detent 20 of the next lower shaped charge 18:: in the carrier 14a. Referring back to FIGURE 5, the release arm 124 only differs from the release arm 28 in that there is extended from the boss '68 an additional detent 28c for interlock with the detent 20a of the bottommost charge of the carrier 14.

Occasionally, when a number of tandem connections are used to make an extremely long gun it may become necescsary to splice the fuse 16 and, additionally, the firing squib conductor wire 24. This is done in common manner through use of the splicing sleeves 128 and 130. It will be noted that a similar splicing sleeve for the conductor wire 24 has been used with the single carrier previously described.

FIGURES 13, 14 and 15 show an alternative embodiment of the carrier wherein like elements carry like numeral designations previously used. Instead of providing a generally cylindrical apertured carrier 14, the modified assembly consists of side bars 132 and spacer discs or rings 134 held in place by the screws 136, the shaped charges 18 being pivoted to the side bars instead of to the carrier 14. The charge caps 64 of the shaped charges 18 are not, however, provided with groove flanges, the detonation fuse being encased in a preformed aluminum tube 138, which protects the fuse from well fluids and abrasive action. In the event discs are used rather than rings, apertures are formed in said discs through which pass the detonation fuse and the conductor 24. The operation of the foregoing modification is precisely the same as that of the assembly utilizing the cylindrical apertured carrier.

While there has been described what is at present considered a preferred embodiment of the present invention, it will be apparent to those skilled in the art that various modifications and changes may be made without departing from the essence of the invention, and particularly that the invention herein presented is adapted to various types and kinds of tools'other than well perforating assemblies. cations and changes as come within the true scope and spirit of the appended claims.

We claim:

1. A well perforating assembly comprising: an elongated carrier having opposed sidewalls and a longitudinal axis; means for lowering said carrier into a well; elongated perforating units positioned between said sidewalls of said carrier with their longer dimensions in axial disposition with respect to said longitudinal axis, each said unit being individually pivotally mounted to said sidewalls on a pivot axis transverse to said longitudinal axis; detent means on the ends of each said unit, said detent means on adjacent units interlocked for retaining said units in said axial disposition, said detent means being releasable upon pivoting of each unit to release the adjacent unit for pivoting; means for latching a terminal one of said units; means operable from the surface of the well for releasing said latching means to release said terminal unit for pivoting; and means operable from the surface of the well for firing said perforating units.

2.,A well perforating assembly comprising: an elongated carrier having opposed sidewalls and a longitudinal axis; means for lowering said carrier into a well; elon- It is intended to cover herein all such modifigated perforating units positioned between said sidewalls of said carrier with their longer dimensions in axial disposition with respect to said longitudinal axis, each said unit being individually pivotally mounted to said sidewalls on a pivot axis transverse to said longitudinal axis; detent means on the ends of each said unit, said detent means on adjacent units interlocked for retaining said units in said axial disposition, said detent means being releasable upon pivoting of each unit to release the adjacent unit for pivoting; resilient means urging said units to pivot from said axial disposition; means for latching a terminal one of said units; means operable from the surface of the well for releasing said latching means to release said terminal unit for pivoting; and means operable from the surface of the well for firing said perforating units.

3. A well perforating assembly comprising: an elongated carrier having opposed sidewalls and a longitudinal axis; means for lowering said carrier into a well; elongated perforating units positioned between said sidewalls of said carrier with their longer dimensions in axial disposition with respect to said longitudinal axis, each said unit being individually pivotally mounted to said sidewalls on a pivot axis transverse to said longitudinal axis; detent means on the ends of each said unit, said detent means on adjacent units interlocked for retaining said units in said axial disposition, said detent means being releasable upon pivoting of each unit to release the adjacent unit for pivoting; resilient means urging said units to pivot from said axial disposition; an explosive cartridge latching a terminal one of said units, said cartridge upon being fired releasing said terminal unit for pivoting; means operable from the surface of the well for firing said cartridge; and means operable from the surface of the well for firing said perforating units, said last-mentioned means being inoperative for such firing during said axial disposition of said perforating units.

4. A well perforating assembly for lowering through well tubing into a well comprising: an elongated carrier having opposed sidewalls and a longitudinal axis; means for lowering said carrier through said tubing to emerge from the lower end thereof in said well; elongated perforating units positioned between said sidewalls of said carrier with their longer dimensions in axial disposition with respect to said longitudinal axis, each said unit being individually pivotally mounted to said sidewalls on a pivot axis transverse to said longitudinal axis; detent means on the ends of each said unit, said detent means on adjacent units interlocked for retaining said units in said axial disposition, said detent means being releasable upon pivoting of each unit to release the adjacent unit for pivoting; resilient means urging said units to pivot from said axial disposition; means for latching a terminal one of said units; means operable from the surface of the well for releasing said latching means to release said terminal unit for pivoting; and means operable from the surface of the well for firing said perforating units, said perferating unit firing means being inoperative for firing said perforating units during said axial disposition and said perforating units when pivotally moved from said axial disposition being adapted to be urged to interlocked axial disposition by the lower end of said tubing upon withdrawal of said carrier upwardly into said tubing.

5. A well perforating assembly comprising: an elongated carrier; means for lowering said carrier into a well; perforating units and an arming means release arm pivotally mounted on said carrier; interlock means on said release arm and on each said perforating unit engageable with interlock means on the next adjacent perforating unit to interlock said perforating units and said release arm in axial disposition with respect to said carrier; means operable from the surface of said well for latching a unit and releasing said perforating units and said arming means release arm in succession for independent pivotal movement from said axial disposition; and means operable to from the surface of said well for firing said perforating units, said means being inoperative for such firing unless said arming means release arm has pivoted at least a predetermined angle from said axial disposition.

6. A well perforating assembly comprising: an elongated carrier; means for lowering said carrier into a well; perforating units and an arming means release arm pivotally mounted on said carrier, said perforating units and arming means release arm being interlocked in axial dis position with respect to said carrier; springs resiliently urging said perforating units and arming means release arm to pivot from such axial disposition; release means maintaining said perforating units and said arming means release arm so interlocked; and electrical circuitry including circuit closing means at the surface of said well, a release means circuit, a firing circuit to provide current for firing said perforating units, and a switch in said firing circuit, said switch being mounted on said carrier and being operatively connected to said arming means release arm to maintain said switch open when said release arm is interlocked in axial disposition and to close said switch when said arming means release arm has pivoted a predetermined angle from said axial disposition.

7. A well perforating assembly comprising: an elongated carrier; means for lowering said carrier into a Well; perforating units and an arming means release arm pivotally mounted on said carrier, said perforating units and arming means release arm being interlocked in axial disposition with respect to said carrier; springs resiliently urging said perforating units and arming means release arm to pivot from such axial disposition; release means maintaining said perforating units and said arming means release arm so interlocked; a release means operating circuit; a firing circuit to provide current for firing said e perforating units; closing means for said circuits at the surface of said well; and a switch mounted on said carrier, said switch maintaining said firing circuit ineffective to provide such current for firing said perforating units while said arming means release arm is interlocked in said axial disposition and being operably connected to said arming means release arm to permit said firing circuit to provide such current upon pivoting of said arming means release arm at least a predetermined angle from said axial disposition.

8. A shaped charge perforating unit for use in an elongated carrier in which the unit pivots from axial disposition with respect to the carrier at least a predetermined angle from axial disposition to firing position, said unit comprising: an enclosed and sealed, elongated, generally cylindrical housing containing a shaped explosive charge; pivot means on said housing providing a transverse pivotal axis therefor; a first detent on one end of said hous ing; and a second complementary detent on the other end of said housing, said detents having detent faces facing in the same direction and lying in a plane including said pivotal axis and being disposed at equal distances from and on opposite sides of a second plane including the longitudinal axis of said housing and intersecting said pivotal axis at right angles.

9. A shaped charge perforating unit for use in an elongated carrier in which the unit pivots from axial disposition with respect to the carrier to firing position at substantially right angles to the axis of the carrier, said unit comprising: an enclosed and sealed, elongated, generally cylindrical housing; a shaped explosive charge in said housing including a booster charge positioned in said housing adjacent one end thereof; pivot means on said housing providing a transverse pivotal axis therefor near said one end of said housing; means on said housing providing a fuse receiving groove arcuate about said pivotal axis and extending from a point at the side of said housing to a point on said one end of said housing adjacent said booster charge, said groove substanding substantially a right angle about said pivotal axis; a first detent on said one end of said housing positioned at one 11 ide of said groove; and a second complementary detent n the other end of said housing, said detents having etent faces facing in the same direction and lying in a lane including said pivotal axis, said second compleientary detent being disposed with respect to said first etent an equal distance from and on the opposite side f a second plane including the longitudinal axis of said .ousing and intersecting said pivotal axis at right angles.

10. A well perforating assembly comprising: an elonated carrier having a longitudinal axis; means for lowerig said carrier into a well; first and second elongated erforating units mounted on said carrier with their lon r dimensions in axial disposition with respect to said Jngitudinal axis for independent pivotal movement from aid axial disposition; resilient means urging said perorating units to pivot as aforesaid from said axial disosition; releasable means locking said first perforating nit to said carrier to restrain said first unit from said ivotal movement; a detent on said second perforating nit; means engaging said detent to restrain said second erforating unit from said pivotal movement, said detent ngaging means being disengaged from said detent in reponse to said pivotal movement of said first perforating nit to release said second unit for said pivotal movement; ieans operable from the surface of the well for actuating aid releasable means to release said first perforating unit or said pivotal movement; and means operable from the urface of the well for firing said perforating units.

11. A well perforating assembly comprising: an elonated carrier having a longitudinal axis; means for lowring said carrier into a well; first and second elongated erforating units mounted on said carrier with longer imensions in axial disposition with respect to said lonitudinal axis for independent pivotal movement from aid axial disposition; resilient means urging said perarating units to pivot as aforesaid from said axial disosition; releasable means locking said first perforating nit to said carrier to restrain said first unit from said ivotal movement; interengaged detents on said first and acond perforating units to restrain said second perforatig unit from said pivotal movement, the detent on said rst unit being disengaged from the detent on said second nit in response to said pivotal movement of said first erforating unit to release said second unit for said pivtal movement; means operable from the surface of the ell for actuating said releasable means to release said rst perforating unit for said pivotal movement; and leans operable from the surface of the Well for firing aid perforating units. a

12. A well perforating assembly for lowering through ell tubing into a well below said tubing comprising: an longated carrier having a longitudinal axis; means for )wering said carrier through said tubing to emerge from 1e lower end thereof in said well; upper and lower elonated perforating units mounted on said carrier with ieir longer dimensions in axial disposition with respect said longitudinal axis for independent pivotal movelent from said axial disposition; resilient means urging rid perforating units to pivot as aforesaid from said xial disposition; releasable means locking said lower erforating unit to said carrier to restrain said lower unit torn said pivotal movement; interengaged detents on said pper and lower perforating units to restrain said upper erforating unit from said pivotal movement, the detent on said lower unit being disengaged from the detent on said upper unit in response to said pivotal movement of said lower perforating unit to release said upper unit for said pivotal movement; means operable from the surface of the well for actuating said releasable means to release said lower perforating unit for said pivotal movement; said upper and lower units, when they have pivoted from said axial disposition and said carrier is Withdrawn upwardly into said tubing, successively engaging the lower end of said tubing and being thereby cammed back to said axial disposition with said detents again interengaged; and means operable from the surface of the Well for firing said perforating units.

13. A perforating gun comprising a tubular shell provided with a plurality of longitudinally spaced apertures located in staggered relationship in opposite portions of the sidewall of said shell, means to locate said shell within a borehole comprising a cable having at least one insulated conductor therein, a plurality of jet cartridges each containing a'jet forming shaped explosive charge respectively carried on pivotal mountings within said shell, the pivotal mounting of each said cartridge being near one of its ends and in a diametral plane of said tubular shell and in a plane parallel to and eccentric to the longitudinal axis of each said cartridge, each of said cartridges being thus mounted to the interior of said shell adjacent one of said apertures with the jet axis of each said cartridge being substantially parallel to the longitudinal axis of said tubular shell, a booster charge for each said explosive charge adjacent the end of each said cartridge at which it is pivotally mounted, means including a substantially rigid latch controlled from the earths surface for pivoting each said cartridge to a position wherein the other end of the cartridge projects outwardly from said shell through its respective aperture, 21 column of detonating material arranged within said shell and normally out of effective physical contact with said booster charges, said eccentric pivotal mounting of each said cartridge permitting the inner diameter of said shell to be substantially equal to the sum of the diameters of one of the respective cartridges and the detonating column, said column of detonating material and said booster charges being so arranged that effective physical contact therebetween is made only when the respective cartridges have been pivoted to their outwardly projecting positions, and means also controlled from the earths surface for detonating said column of detonating material.

References Cited in the file of this patent UNITED STATES PATENTS 2,582,719 Ramsey Jan. 15, 1952 2,616,370 Foster Nov. 4, 1952 2,629,325 Sweetman Feb. 24, 1953 2,639,770 Huber May 26, 1953 2,644,519 Kanady July 7, 1953 2,664,156 Allen Dec. 29, 1953 2,664,157 Abendroth Dec. 29, 1953 2,734,456 Sweetrnan Dec. 14, 1956 FOREIGN PATENTS 1,023,832 France Jan. 7, 1953 1,029,798 France Mar. 11, 1953 UNITED STATES PATENT OFFICE 'CERTIFEATE 0F CQRRECTION Patent No, 3,067,679 December ll 1962 Blake Ma Caldwell et al.

It is hereby certified that error appears in the above numbered pat ent requiring correction and that the said Letters Patent should read as corrected below.

Column 10, line 73,,

for "substalrlding" read subtending column ll line 32 after "with" insert their Signed and sealed this 16th day of July 1963.,

(SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE, OF CORRECTION Patent No. 3,067,679 December 11 1962 Blake M. Caldwell et all,

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 10, line 73, for "substanding" read s'ubtending column 11 llne 32, after "with" insert their Signed and sealed this 16th day of July 1963.,

(SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents 

